RTextTools - A supervised machine learning package written in R used for automatic text classification (e.g. congressional bills, legal opinions, etc.). The package provides cross-platform support for nine algorithms (svm, maxent, glmnet, etc.).

maxent - A supervised machine learning package for multinomial logistic regression based on Yoshimasa Tsuruoka's C++ maximum entropy implementation. The package includes an interface for compressed sparse matrices and tools for model tuning.

sentiment - A sentiment analysis package that includes naive Bayes classifiers for identifying positive/negative sentiment and six different emotions. The tool uses Janyce Wiebe's subjectivity lexicon and Carlo Strapparava and Alessandro Valitutti's WordNet-Affect dataset.

PeekFeed - PeekFeed was a service that delivered millions of real-time RSS updates to thousands of user inboxes based on their scheduling options. Featured on Gizmodo, GearDiary, and SlashGear.